We aim to develop a theoretical and experimental model for selective coagulation of choroidal vessels. Although lasers occupy an important role in the treatment of ocular disease, the development of ophthalmic lasers has been, in large measure, empirical because the availabililty of laser sources determined which wavelengths, pulsewidths, and energies were studied. The development of future applications of lasers in ophthalmology is likely to rely on the development of lasers and techniques to confine laser effects to specific tissue or ultrastructural targets. We propose to (1) extend our preliminary studies in developing and experimentally evaluating a strategy (selective photothermolysis) for optimizing selective closure of choroidal and retinal vessels while minimizing damage to the neural retina; (2) use theoretical models to predict which wavelengths, pulse durations and incident exposure energy densities can best achieve site selective heating at the rates necessary; (3) use selectively targeted dyes to make selective photothermolysis possible in the near infrared region, after first modelling the technique to select the best available dyes and wavelengths. This approach is of great potential value because dye-targeted selective photothermolysis at wavelengths which avoid significant direct effects upon the retinal pigment epithelium and neural retina may be used for a variety of procedures, potentially reducing damage to the neural retina; (4) perform in animal models a series of studies designed to correlate sequential clinical, histological and ultrastructural responses to laser exposures with theoretical predictions based on physical models and with therapeutic goals. Alexandrite, erbium and tunable dye lasers will be used in these studies.